Put the following events of translational elongation (the stage in translation that occurs after initiation) in the order that they occur, beginning with the first step at the top.
1. The ribosome moves down the mRNA by one codon, and a tRNA carrying the third amino acid comes into place.
2. After the first amino acid has been brought to the ribosome, a tRNA carrying the second amino acid of a protein binds to the second codon.
3. A covalent bond forms between the first and second amino acids.
4. The ribosome releases the first tRNA.
5. The ribosome releases the second tRNA.
6. A covalent bond forms between the second and third amino acids.